Lumens Per Watt

And is that a complete setup or do you still need 2 110v to E27 lamp plugs and 2 Y's? Does that include a reflector? To reach 40,000 lumens you would need 5 bulbs, plus 5 reflectors, plus the adapter plugs etc.. Performance can't be compared unless as I said before, your using a very small grow area. (Like 2' x 2' or less)

The reason performance can't be compared is because although your small little CFL may put out 8,000 lumens, it's only doing so from a very small source point, which means light intensity will drop off and the CFL will cover a much smaller area compared to the 4' T5 which is throwing 5,000 lumens accross 4 feet.

Best advice is to get a light meter which 99% of CFL growers fail to do. If you looked at a side by side comparison of a 4' 8 bulb T5 HO lamp and 5 of those rosebud CFL's in a 2' x 4' area, you would find the light meter shows multiple pockets of significantly reduced light compared to the 4' T5's.

I hope that makes sense.

Click to expand...

Here is a set i have. I used a quantum PAR and lux meter to read output and it is pretty even through out the four foot length of my fixture. My fixture is using 4 X "250" watt 8U CFL's. I say "250" watt because when i take an current reading it only draws 4 amps @ 115 volts or 460 watts not 1000! It seems the cfl's are drawing far less power than what they are advertised as. When you look at a 8U bulb , the tubes are actually T5 tubes and if you measure these tubes, it would stretch out to almost 15 feet of tubing all in a compact package. T5 simply means 5/8 in diam tube. 15 ft of standard T5 not HO works out to about the same wattage as one of these 8U's.
As for the readings im getting a consistent 600 uMol/s at 18" above over an entire 4X3 ft area. i'm going to do a comparison with 1000 watt HPS and see how it compares but 600uMol/s is very good for any kind of lighting.

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I know what your saying but believe me the lights you have all the way on the left are not going to provide much intensity all the way to the right. The 8 bulb T5 bulbs are so close together, there is not an inch of space that is not within good intensity range of ALL 8 bulbs. I swear you would have a much better light reading with HO 4' T5's in the same wattage. Not to mention the heat. You could literally have a mature plant 1 inch under the HO T5 with zero cooling fans. I doubt you could do the same with those bulbs.